# Noise from a curved road

laurence44 | 16:26 Sat 06th Jun 2009 | Science
Consider a straight busy fast road. At a constant distance from it the noise level is constant. What happens if the road curves?
Intuition suggests that on the inside of the bend a point will receive noise from slightly more road, and one the same distance away on the outside of the bend will be quieter because it receives noise from a reduced length of road.
A solution which ignores traffic variations, third dimension effects like refraction and obstacles like buildings and trees would be of interest, but my capacity to convert my intuition into a mathematical equation and solve the equation has withered from lack of use. If someone were willing to give me the benefit of a few minutes' thought I would be very grateful and fascinated!
Thanks!

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The level of noise you hear will be dependent on your distance from the noise source. On the inside of the bend you will be closer to a greater length of the road than if the road were straight, and so the total noise you hear will be more. (Imagine being in the center of a road built in a circle round you). Conversely, on the outside of the bend you will be further away from a greater length of the road than with a straight road, and the total noise will be less,
You probably do too much thinking laurence44 :�)

Just too make things more interesting consider that the tyres on the outside of the curve travel at a greater speed than the inside ones so will make more noise.
The sound output from the tyre travelling in an arc is greater than that for straight line travel. (there is another force component: friction force = centripetal force)

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